A Pre-Columbian Cavity

Archeologist Steven Baker was working at Sky Aerie Overlook, the site of some early Indian shelters on a hill in Rio Blanco County, Colorado, when he unearthed a stack of bones. Oddly enough, the fragmented skeletons were partially buried under a hearth. But the real surprise came when Baker forwarded the spoils to Tim White’s Laboratory for Human Evolutionary Studies in Berkeley, California.

Sorting through the bones, White noticed an unusual hole on the surface of a human canine tooth, wobbly but intact in its jaw. We’ve worked with a lot of skeletal material, graduate student David DeGusta recalls, but we’ve never seen a hole like this. The tooth, which dates from between the years 800 and 1200, appears to be the first evidence of dentistry in the Southwest and one of only three or four prehistoric teeth in the world that bear the signs of such work.

White’s team became convinced of the nature of the hole after studying it with a scanning electron microscope. Inside the hole was a series of neat, systematic striations running along its sides. This suggested to us, says DeGusta, that someone drilled out this hole. It didn’t look like it was carved by any sort of chemical process, and it’s not like a rat is going to gnaw a perfect hole on the top of the tooth. The researchers also noticed a scar on the jaw near the tooth, the impression of what must once have been a rather painful abscess.

With a motive established and evidence documented, all the researchers needed was a good reenactment. That was easily done. They took some obsidian, honed it into a drill bit, and mounted the stone on a small stick. Why obsidian? Obsidian was a relatively common material for making tools, says DeGusta. We also happened to have a large supply of it in the lab.

The researchers then took a modern canine tooth very similar to the prehistoric one and went at it with their obsidian drill. Using an electron microscope once again, they could see that their handiwork produced striations identical to those found in the Sky Aerie canine. Researchers in Denmark have recently found similar marks in a Neolithic tooth, suggesting that primitive dentistry was geographically widespread, although it was probably not a common practice.